The present invention relates to a data processor in the form of a semiconductor integrated circuit and, more particularly, a debugging aid function in a data processor. The invention relates to a technique effective for application to, for example, tracing of a plurality of kinds of internal buses built in a data processor.
In a data processor such as a microcomputer, a Central Processing Unit (CPU) and other circuit modules are mounted. Because of demand of higher functions, the number of built-in circuit modules increases and the configuration of internal buses is accordingly becoming complicated. In the case of debugging a system by using the data processor, the internal state of the data processor has to be monitored and provided for debugging while executing a target program. However, the inventor herein has found that, in circumstances that the circuit configuration of the data processor and bus configuration are complicated, it is difficult to monitor internal information of various internal buses while executing the target program and, further, monitor the bus information in a real time manner or in an almost real time manner.
Literature of a technique paying attention to a function of tracing internal data in a data processor includes Japanese Unexamined Patent Application Publication Nos. Hei 11(1999)-219303 and Hei 3(1991)-90955 disclosing a tracing method of a multiprocessor. In the former literature, monitoring of a plurality of buses and addition of identification information of a processor to trace information are not considered. The latter literature describes an example of using identification information indicative of a CPU as the source of bus information.